Morbid obesity is a chronic condition. Gastric limiting techniques (e.g. “adjustable gastric banding” or AGB) are employed by surgeons to treat morbidly obese people who cannot lose weight by traditional means. In AGB, a gastric “band” made of an elastomer is placed around the stomach near its upper end. This creates a small pouch with a narrow passage into the rest of the stomach (“stoma orifice”), thus limiting the amount of food intake (“eating”) by creating a feeling of fullness or uneasiness and by usually extending the time frame required to empty the pouch into the rest of the stomach. To control the size of the stoma orifice, the gastric band can be pressurized or depressurized by a physician. As a non-limiting example, the pouch is usually of a size of 50 cc to 5 cc, preferably 20 cc to 8 cc, and more preferably of about 15 cc. The stoma size can be increased or decreased with a saline solution by using a needle and syringe to access a small access port placed under the skin. The stoma orifice is governed by the amount of stomach tissue inside the band at the banding site. A desired passage size is about 12 mm in internal diameter.
The aim of restricting passage of food and liquids is to force the patient to change his/her eating behavior and thereby to induce a significant amount of weight loss. Researchers have demonstrated that the initial weight loss results after AGB are less predictable then those after gastric bypass. Patients after surgery are advised to chew their food thoroughly, eat slowly, take small bites, avoid certain foods, etc. Often, a large number of these patients do not adopt the required behavior and instead, eat forcefully, vomit, and intermittently suffer stoma occlusion events. These may result eventually in such complications as pouch enlargement, band erosion, reflux, and esophageal enlargement. In some cases, additional surgical interventions may be required.
The observation of gastric band action and the adjusting of stoma orifice by inflation/deflation are facilitated by X-ray imaging. A physician or technician acts to adjust (increase or decrease) the volume of fluid in the band based on inputs from the X-ray imaging. The volume decrease is done by removing an amount of fluid from the band via the external access port and fill line. Alternatively, components for adjusting the size of the gastric band may be implanted within the patient and, when a physical parameter such as intra-band pressure related to the patient food passage is determined, an external control unit outside the patient's body may be operated to power the implanted components to adjust the size of the band.
Monitoring the activity of the pouch created between the lower esophagus sphincter and the gastric band may generate important information related to the eating behavior of patients. Physiological parameters obtained by such monitoring may be useful to help a patient control his/her obesity, manage his/her diabetes, and monitor his/her gastro-esophageal reflux disease and the like.
Adjustable gastric restriction devices with sensors and actuators which enable control of the stoma orifice are disclosed for example in US patent applications No. 20070156013 by Birk and 20060173238 by Starkebaum. Birk discloses a self-regulating gastric band with pressure data processing, relates to a band adjustment assembly which is provided for implanting with the gastric band that includes a sensor for sensing fluid pressure in the expandable portion. The band adjustment assembly further includes a pump assembly connected to the expandable portion and to a controller that can operate the pump assembly to adjust the volume of the fluid in the band based on the sensed fluid pressure. Starkebaum's invention relates to a dynamically controlled gastric occlusion device that monitors at least one physiological parameter that varies as a function of food intake and controls the degree of gastric constriction of an occluding device, such as a gastric band, based on the monitored physiological parameter. In an embodiment, the dynamically-controlled gastric occlusion device controls the degree of gastric constriction based on time. The occluding device is dynamically opened or closed to either permit or prevent the passage of food through the_gastrointestinal (GI) tract.
U.S. Pat. No. 5,724,025 to Tavori discloses a portable vital signs monitor in communication with a plurality of sensors capable of implantation, with two way communication, also allowing current diagnosis of a live body, possible reasons for abnormal diagnosis, based on physical data, anticipated behavior of the body and monitoring physical changes resulting from actual treatment.
A large number of studies have determined the following:                1) Pouch volume and stoma size are important determinants for the success of AGB.        2) Proper stoma adjustment can effect immediate and late results of the AGB and reduce complications such as Spherical Pouch Dilatation (SPD).        3) Fast eating or improper chewing of the food can lead to excessive pouch enlargement and impaired surgical results.        4) Adoption of favorable eating behavior is imperative for long term success of the AGB        5) Adoption of mal-eating behaviors can reduce the success rate of AGB.        
Although gastric bands can limit food intake, it is worth recognizing that eating is a form of behavior that can be defined according to its structure (frequency duration and size of eating episodes). This pattern of behavior can be further analyzed at the level of a single meal, where the same structure (frequency duration and size of eating episodes—bites) rules and defines the meal size. In principle, this behavior operates through the skeletal musculature and is subject to conscious control. Therefore, people should be able to volitionally decide when and how to control their own eating. In practice, people find it extremely difficult to exert control and many obese people claim that their eating is out of (their) control.
AGB procedures are not known to provide a patient with visual data or information regarding his/her eating behavior pattern, yet the patient is expected to adopt different eating behavior with respect to frequency, duration or size of bite or meal. The realization and visualization of eating behavior patterns is required to the patient in order to induce conscious and correct eating behavior modification. Therefore there is a need for a tool that will provide the AGB obese patients a guided and controlled eating “pacer” that will enable them to learn and gain a new control over their eating behavior.
Out of the clinical literature from the last 15 years and over 500,000 patients with AGB it is clear that it is very difficult to obtain-hard quantitative data on the true food intake behavior of AGB obese patients. It is clear that in some AGB obese individuals, habitual food intake or its caloric value are greater than it is normally assumed to be and is often erratic and apparently unregulated. In order for health care givers to be able to advice and guide those patients to better regulate eating habits and behavior, there is clearly a need for a method and apparatus that will enable them to monitor and obtain objectively recorded eating behavior patterns. It would also be advantageous to have systems and methods to improve the action of AGB by automatically releasing excessive pressure buildups.